JP2005144861A - Calibration method of printer, printer and recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply and surely carry out calibration of a printer by visual observation without using a densitometer. <P>SOLUTION: A Y reference pattern 13, an M reference pattern 14, and a C reference pattern 15 to be printing density criteria are printed in the form of gradations at a leading end part of a long color thermal recording sheet. A color thermal printer forms a sample print 21 by solid printing a Y calibration pattern 18, an M calibration pattern 19 and a C calibration pattern 20 of predetermined optical density values adjacently above each of the reference patterns 13-15. The user observes the sample print 21, selects a part approximate to a printing density of each of the calibration patterns 18-20 among each of the reference patterns 13-15, and specifies a density number printed below the selected part. When the density number is inputted to the color thermal printer, density correction for every color is carried out automatically. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a calibration method for adjusting the print density of a printer, a printer that implements the calibration method, and a recording material used in the printer.

  The applicant has developed a color thermal recording paper in which a plurality of thermal coloring layers, each of which is colored cyan, magenta, yellow, etc., are sequentially formed on a support, and a color thermal printer for printing on the color thermal recording paper. Manufactured and sold. The color thermal recording paper is set so that the thermal sensitivity of the lowermost thermal coloring layer (cyan) is lower, and the uppermost (yellow) and middle (magenta) thermal coloring layers are fixable to ultraviolet rays. Is granted. The color thermal printer is a thermal head that presses against a color thermal recording paper and applies thermal energy to selectively develop each thermal coloring layer, and a light fixing device that fixes the yellow and magenta thermal coloring layers. It has.

  It is known that the color development sensitivity of color thermal recording paper changes with time, such as exposure and moisture retention. It is also known that the color density and gray balance of color thermal recording paper change due to manufacturing variations of color thermal printers and adjustment variations after manufacturing. In order to reduce the variation in color density and gray balance, various calibration methods for adjusting a color thermal printer have been invented (see, for example, Patent Documents 1 to 3).

  In the calibration method described in Patent Document 1, a sample print in which a calibration pattern is printed by a color thermal printer to be adjusted is created, and the calibration pattern is measured with a densitometer inside or outside the printer. Then, a correction value is calculated based on the measurement result, and the color thermal printer is adjusted and corrected.

  Further, in the calibration method described in Patent Document 2, in order to prevent color thermal recording paper from being wasted by calibration, a recording paper roll in which a long color thermal recording paper is wound in a roll shape is used as a recording medium. A calibration pattern is printed on the tip that is used and cut and discarded during printing. Furthermore, in the calibration method described in Patent Document 3, the leading end of the recording paper roll is fixed in advance in order to shorten the printing time of the calibration pattern.

  A calibration method that does not use a densitometer is also known. In this calibration method, a sample print created by a color thermal printer is compared with a reference print or color sample, and a deviation in density and gray balance is specified by visual observation. The color thermal printer is adjusted and corrected based on the specified result.

JP 2001-058423 A JP 2001-239731 A JP 2001-171231 A

  The calibration method using the densitometer requires a densitometer inside or outside the color thermal printer, which causes a problem of an increase in equipment cost. There is also a problem that the installation size and installation space of the color thermal printer are increased by providing a built-in space for the densitometer and a measurement space for the densitometer.

  On the other hand, in the calibration method that does not use the densitometer, the above problem does not occur. However, since the color sample itself changes with time such as fading, the adjustment reference becomes unstable. Further, when a color sample color material or paper material different from the color thermosensitive recording paper is used, the color appearance changes depending on the observation light source, and the adjustment reference becomes unstable. Furthermore, there is a problem in that it is difficult to make a stable adjustment because the visual adjustment becomes large based on experience.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and to easily and surely calibrate a printer visually without using a densitometer.

  In order to solve the above problems, the printer calibration method of the present invention prints a calibration pattern with a predetermined optical density value of a recording head on a recording material on which a plurality of reference patterns having different printing densities are printed in advance. The current print density of the printer can be checked by comparing the calibration pattern with each reference pattern. Also, a density approximate reference pattern having a print density approximate to the print density of the calibration pattern is selected from a plurality of types of reference patterns, and the optical density value of the density approximate reference pattern and the calibration pattern print are used. The print density of the recording head is adjusted using the difference from the predetermined optical density value. Further, by inputting the type of density approximate reference pattern to the printer, the printer automatically adjusts the print density of the recording head.

  Further, in order to facilitate the comparison between the calibration pattern and the reference pattern, the reference pattern was printed by the same printing method using a reference printer or a marking device. Further, a calibration pattern was printed adjacent to the reference pattern. In addition, the reference pattern is continuously printed in gradation.

  Furthermore, in order to perform calibration of the printer periodically, a calibration pattern is printed when the recording material roll is set in the printer. Further, in order not to waste the recording material, the reference pattern and the calibration pattern are printed on the leading end portion of the recording material which is a blank portion to be cut and discarded.

  Further, when the printer is a color printer, the reference pattern and the calibration pattern are printed for each color, compared for each color, and the print density of the recording head is adjusted for each color.

  In order to solve the above problems, a printer of the present invention includes a recording head for printing on a recording material, calibration data generating means for generating print data of a calibration pattern having a predetermined optical density value, and the calibration data. Selected as a reference pattern having a print density that approximates the print density of the calibration pattern, and a head drive means that drives the print head based on the print data of the print pattern and prints the calibration pattern in the vicinity of the reference pattern of the recording material An input means for inputting the type of the density approximate reference pattern and a density adjusting means for adjusting the print density of the recording head in accordance with the input content are provided.

  Further, in the case of a printer that prints the first to third colors on the color thermal recording paper by the thermal head, the calibration pattern is printed for each of the first to third colors, and the type of density approximate reference pattern is also selected. Each color is input to the input unit, and the print density is adjusted by the density adjustment unit for each of the first to third colors.

  Further, as the recording material used in the printer, a plurality of types of reference patterns having different printing densities were printed in advance outside the recording area. Furthermore, the reference pattern was continuously printed in gradation. Also, a reference pattern is printed for each of a plurality of types of colors printed by the printer. Further, a reference pattern is printed on the tip portion that is cut and discarded after printing on the recording area.

  According to the printer calibration method, the printer, and the recording material of the present invention, the calibration pattern is compared with a plurality of types of print density reference patterns printed on the recording material. The optical density of current printers can be specified easily and reliably. In addition, since the reference pattern printed on the same recording material by the same printing method is used as a color sample, the reference pattern and the calibration pattern do not appear to differ in color depending on the observation light source.

  In addition, since the print density of the print head is adjusted using the difference between the optical density value of the density approximate reference pattern and the optical density value of the calibration pattern, complicated calculation and control are required to calculate the density correction amount. Do not need. Furthermore, since the printer automatically adjusts the print density of the recording head by inputting the type of density approximate reference pattern to the printer, there is no need for complicated adjustment work, and it is easy for anyone to use the printer. Calibration can be performed.

  In addition, since the calibration pattern is printed adjacent to the reference pattern or the reference pattern is continuously printed in a gradation, it is easy to compare the calibration pattern with the reference pattern. Further, since the calibration pattern is printed when the recording material roll is set in the printer, the printer can be calibrated periodically. Further, since the reference pattern and the calibration pattern are printed at the leading end of the recording material that is cut and discarded, the recording material is not wasted.

  Further, when the printer is a color printer, the print density of the recording head can be adjusted for each color, so that the gray balance can also be adjusted.

  FIG. 1 is a schematic diagram showing the configuration of a color thermal printer embodying the present invention. The color thermal printer 2 uses a long color thermal recording paper 3 as a recording material. The color thermal recording paper 3 is supplied to the market in the form of a recording paper roll 4 wound in a roll, and is set in the roll chamber 5 of the color thermal printer 2.

  As shown in FIG. 2, the color thermosensitive recording paper 3 has a cyan thermosensitive coloring layer 7, a magenta thermosensitive coloring layer 8, a yellow thermosensitive coloring layer 9, and a protective layer 10 formed in this order on a support 6. The yellow thermosensitive coloring layer 9 as the uppermost layer is set to have the highest thermal sensitivity, and develops yellow with a small amount of thermal energy. The cyan thermosensitive coloring layer 7 as the lowermost layer has the lowest thermal sensitivity and develops cyan with a large amount of thermal energy. The yellow thermosensitive coloring layer 9 loses its coloring ability when irradiated with near ultraviolet rays of 420 nm. The magenta thermosensitive coloring layer 8 develops magenta with a thermal energy intermediate between the yellow thermosensitive coloring layer 9 and the cyan thermosensitive coloring layer 7, and loses the coloring ability when irradiated with 365 nm ultraviolet rays. For example, a color thermosensitive recording paper having a four-layer structure with a black thermosensitive coloring layer may be used.

  As shown in FIG. 3 and FIG. 4, yellow (Y) and magenta (color samples) used for the calibration process of the color thermal printer 2 are placed at the leading end of the color thermal recording paper 3 pulled out from the recording paper roll 4. Reference patterns 13 to 15 for each color of M) and cyan (C) are printed in a band shape along the width direction of the color thermal recording paper 3. Each of the reference patterns 13 to 15 is printed so that the print density gradually increases from the left to the right in the drawing, that is, in a gradation.

  Most of the leading end portion of the color thermal recording paper 3 on which the reference patterns 13 to 15 are printed is a blank portion that is cut and discarded at the time of printing. Therefore, the color thermal recording paper 3 is not wasted, and the number of prints that can be printed by the recording paper roll 4 is not extremely reduced. These reference patterns 13 to 15 are printed by a color thermal printer (reference printer) which is a standard for setting the print density and gray balance of the color thermal printer 2 after the recording paper roll 4 is manufactured.

  Under each of the reference patterns 13 to 15, density numbers “1 to 10” are printed from the left end toward the right end. This density number represents the density at each gradation position of the reference patterns 13-15. The density number is different from the actual optical density value. For example, the optical density value (OD) of the portion of the Y reference pattern 13 with the density number “1” is “OD0.3”, and the portions of the density position numbers “5” and “10” are “OD0.5” and It is “OD0.7”.

  The range of the optical density of the reference patterns 13 to 15 is determined based on the range of variations in print density that can occur in the color thermal printer 2, that is, the design accuracy of the color thermal printer 2. For this reason, the range of the optical density of the reference pattern is narrowed in an industrial color thermal printer with high design accuracy, and the range of the optical density of the reference pattern is widened in an inexpensive domestic color thermal printer.

  As shown in FIG. 5, in the calibration process of the color thermal printer 2, yellow (Y), magenta (M), and cyan are positioned above the reference patterns 13 to 15 and adjacent to the reference patterns 13 to 15. A sample print 21 in which the calibration patterns 18 to 20 of each color in (C) are printed in a band shape is created. The calibration patterns 18 to 20 for each color are solid-printed with, for example, a predetermined optical density value “OD0.5” of the color thermal printer 2 on which calibration processing is performed.

  In the calibration process, the user compares the calibration patterns 18 to 20 and the reference patterns 13 to 15 for each color, and the actual density of the calibration patterns 18 to 20 is the density number of the reference pattern 13 to 15. Is specified. When the print density of the color thermal printer 2 matches the print density of the reference printer, the density numbers of the calibration patterns are all “5”. As a result, the user can easily compare the print density level of the color thermal printer 2 being used with the reference printer.

  In addition, since the reference pattern, which is a color sample to be compared with the calibration pattern, is printed on the same recording paper by the same printing method, it does not appear that the hue differs depending on the observation light source. Furthermore, since the reference patterns 13 to 15 are gradation and the calibration patterns 18 to 20 are printed in contact with the reference patterns 13 to 15, the density number of the portion where the reference pattern and the calibration pattern appear to be connected is This is the density number of the calibration pattern. Thereby, a reference pattern having the same print density as the calibration patterns 18 to 20 can be easily found.

  If each of the reference patterns 13 to 15 is colored after printing by the reference printer, the function as a color sample cannot be performed. Therefore, after printing the Y reference pattern 13, the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer in the Y reference pattern 13 are fixed. Further, within the printing range of the M reference pattern 14, the yellow thermosensitive coloring layer is fixed before the magenta color is developed, and the magenta thermosensitive coloring layer is fixed after the magenta printing. Further, within the printing range of the C reference pattern 15, both the yellow thermosensitive coloring layer and the magenta thermosensitive coloring layer are fixed before the cyan printing. Further, when the reference patterns 13 to 15 are printed by the reference printer, fixing to the portion where the calibration patterns 18 to 20 are printed is not performed.

  An optical sensor 23 for detecting the loading of the recording paper roll 4 is provided in the roll chamber 5 in which the recording paper roll is set. The optical sensor 23 detects the end surface of the core 4 a of the recording paper roll 4 and inputs a detection signal to the system controller 25.

  A paper feed roller 27 rotated by a carry motor 28 contacts the outer peripheral surface of the recording paper roll 4 set in the color thermal printer 2. The conveyance motor 28 is a pulse motor and is driven by pulses input from the motor driver 29. When the paper feed roller 27 rotates counterclockwise in the figure, the recording paper roll 4 rotates clockwise in the figure, and the color thermal recording paper 3 is sent out from the recording paper roll 4. Conversely, when the paper feed roller 27 rotates in the clockwise direction in the figure, the recording paper roll 4 rotates counterclockwise in the figure to rewind the color thermal recording paper 3.

  From the roll chamber 5 in which the recording paper roll 4 is set, a horizontal conveyance path through which the color thermal recording paper 3 fed from the recording paper roll 4 is conveyed is provided. In this transport path, a pair of transport rollers 32 for transporting the color thermosensitive recording paper 3 in between and a pair of paper discharge rollers 33 are arranged. The conveyance roller pair 32 and the paper discharge roller pair 33 are composed of capstan rollers 32a and 33a rotated by the conveyance motor 28 and pinch rollers 32b and 33b pressed against the capstan rollers 32a and 33a. 3 is reciprocally conveyed in the left A direction (paper feeding direction) in the drawing and in the left B direction (rewinding direction) in the drawing. A discharge port 34 for discharging the printed color thermal recording paper 3 to the outside of the printer 2 is provided on the downstream side of the discharge roller pair 33 in the A direction.

  A thermal head 37 and a platen roller 38 are arranged between the recording paper roll 4 and the conveyance roller pair 32 so as to sandwich the conveyance path of the color thermal recording paper 3. The thermal head 37 is disposed above the transport path, and has a heating element array 39 on its lower surface, in which a large number of heating elements each for printing one pixel are arranged in a line along the main scanning direction. ing.

  The platen roller 38 is disposed below the conveyance path at a position facing the heating element array 39, and can be moved in the vertical direction by a shift mechanism such as a cam or solenoid, and is attached to the thermal head 37 by a spring (not shown). It is biased in the direction of pressure contact. The platen roller 38 is lowered by a shift mechanism at the time of paper supply and paper discharge, and forms a gap with the thermal head 37.

  The thermal head 37 sandwiches the color thermal recording paper 3 between the heating element array 39 and the platen roller 38 when the color thermal recording paper 3 is conveyed in the A direction by the conveyance roller pair 32. In the heating element array 39, each heating element is heated to a predetermined temperature by the head driver 42, so that each thermal coloring layer of the color thermal recording paper 3 is colored. The platen roller 38 is driven to rotate in accordance with the conveyance of the color thermal recording paper 3 and stabilizes the contact state between the color thermal recording paper 3 and the heating element array 39.

  An optical sensor 44 that detects the leading edge of the color thermal recording paper 3 is incorporated on the downstream side of the conveyance roller pair 32 in the A direction. The detection signal of the optical sensor 44 is input to the system controller 25 and used for controlling the color thermal printer 2.

  On the downstream side in the A direction of the optical sensor 44, an optical fixing unit 47 is disposed so as to face the recording surface of the color thermal recording paper 3. The light fixing unit 47 fixes the yellow heat-sensitive recording layer 9 by emitting near-ultraviolet light having an emission peak of 420 nm and fixing the magenta thermosensitive coloring layer 8 by emitting ultraviolet light having an emission peak of 365 nm. A fixing light source 49 for magenta. These light sources are driven to emit light by the lamp driver 50.

  A cutter 52 that cuts the color thermosensitive recording paper 3 in a direction perpendicular to the longitudinal direction is disposed between the optical fixing device 47 and the paper discharge roller pair 33. The cutter 52 includes a fixed blade 52a fixedly disposed below the transport path and a movable blade 52b disposed above the transport path and movable in the vertical direction by the cutter driving mechanism 53. The fixed blade 52a And the moving blade 52b sandwich the color thermal recording paper 3 and cut it.

  FIG. 6 is a block diagram illustrating a configuration of a system controller 25 that controls each unit of the color thermal printer 2. The system controller 25 includes a well-known microcomputer, and includes a CPU 55 that performs various arithmetic processes according to control, and a memory unit 56. The CPU 55 includes a calibration data generation unit 57, an image calculation processing unit 58, and a calibration calculation processing unit 59. The memory unit 56 is divided into a plurality of memory areas, and a program memory 60, an image data memory 61, a density number memory 62, and a correction parameter memory 63 are provided. The program memory 60 stores a control program that controls the operation of the color thermal printer 2 and is read out by the CPU 55 as appropriate.

  The image data memory 61 stores image data input from an external device connected to the color thermal printer 2. The image data stored in the image data memory 61 is read out to the image calculation processing unit 58. The image arithmetic processing unit 58 performs known color correction and gradation correction on the image data, converts the image data into print data for driving the thermal head 37, and inputs the print data to the head driver 42. The head driver 42 adjusts the energization time of each heating element of the heating element array 39 based on the print data, and prints pixels having a color and density corresponding to the print data on the color thermal recording paper 3.

  The density number memory 62 stores the density number of each color input from the density number input unit 65 during the calibration process of the color thermal printer 2. As shown in FIG. 7, for example, the density number input unit 65 includes a numeric keypad 67 from 0 to 9, an enter key 68 for confirming input, and an LCD 69 for displaying input contents. The density number input unit 65 is provided outside the color thermal printer 2 or at a position where it is hidden during normal operation and can be easily accessed during calibration processing.

  On the LCD 69 during the calibration process, for example, a message prompting the input of a density number such as “Y =?” Is displayed. As described above, the user compares the Y reference pattern 13 with the Y calibration pattern 18, searches the Y reference pattern 13 for the same density as the Y calibration pattern 18, and inputs the density number with the numeric keypad 67. . After inputting the Y density number, if the enter key 68 is pressed to confirm, then the message “M =?” Is displayed on the LCD 69, prompting the user to input the density number of the M calibration pattern 19. Thereafter, the magenta and cyan density numbers are input in the same manner as the yellow density number.

  If there is no need to perform calibration processing, it is desirable to immediately finish the calibration processing so that printing can be performed. For this reason, the density number input unit 65 may be provided with a cancel button or the like for forcibly ending the calibration process. If the density number input unit 65 is not operated for a certain time, the calibration process is ended. May be.

  The calibration data generation unit 57 operates when the recording paper roll 4 is set in the color thermal printer 2, generates print data of the calibration patterns 18 to 20, and inputs the print data to the head driver 42. The head driver 42 drives each heating element of the thermal head 37 based on this print data, and prints the calibration patterns 18 to 20 adjacent to the reference patterns 13 to 15.

  Based on the Y, M, and C density numbers read out from the density number memory 62, the calibration calculation processing unit 59 corrects the energization time of each heat generating element when the head driver 42 prints each color image. A correction parameter, an M correction parameter, and a C correction parameter are calculated. The Y to C correction parameters calculated by the calibration calculation processing unit 59 are stored in the correction parameter memory 63 and are read out by the head driver 42 when printing each color.

  FIG. 8 is a graph showing an outline of a correction parameter calculation method performed by the calibration calculation unit 59. In this graph, the vertical axis represents the correction parameter, the horizontal axis represents the density number, and the straight line X represents the density correction characteristic. As described above, in the calibration process, Y to C calibration patterns 18 to 20 of “OD 0.5” are printed on the color thermal recording paper 3. When the optical density of the calibration patterns 18 to 20 is actually “OD0.5”, the density in the vicinity of the density number “5” of the reference patterns 13 to 15 matches the density of the calibration patterns 18 to 20. When this result is applied to the graph of FIG. 8, since the correction parameter is “0” when the density number is “5”, it is not necessary to correct the print density.

  On the other hand, when the density number of the calibration patterns 18 to 20 is “2”, the actual optical density value is about “OD 0.3”. It can be seen that the print density is lower than “OD 0.5”. When this result is applied to the graph of FIG. 8, a correction parameter that increases the print density is calculated. Similarly, when the density number of the calibration patterns 18 to 20 is “8”, the actual optical density value is about “OD0.6”, and the print density set in the color thermal printer 2 is set. Result in high. The correction parameters at this time are set so that the print density becomes light.

  As described above, since the correction parameter can be calculated based on the difference between the optical density value of the reference patterns 13 to 15 and the optical density value used for printing the calibration patterns 18 to 20, complicated calculation and control are possible. Therefore, even if an inexpensive system controller with low processing capability is used, the correction parameter can be obtained quickly. Further, since the density correction can be performed simply by inputting the density number of the calibration pattern, anyone can calibrate the color thermal printer.

  Next, the operation of the above embodiment will be described with reference to the flowchart of the calibration process in FIG. 9 and the print process in FIG. In order to use the color thermal printer 2, it is necessary to set the recording paper roll 4 in the color thermal printer 2. First, the recording paper roll 4 is taken out from the packaging bag having light shielding properties and moisture resistance. As shown in FIGS. 3 and 4, a Y reference pattern 13, an M reference pattern 14, and a C reference pattern 15 are printed in advance on the leading end portion of the color thermal recording paper 3 of the recording paper roll 4. . Next, the lid of the color thermal printer 2 roll chamber 5 is opened, the recording paper roll 4 is set, and the lid is closed.

  When the recording paper roll 4 is set in the roll chamber 5, the optical sensor 23 is activated. The optical sensor 23 detects the core 4 a of the recording paper roll 4 and inputs a detection signal to the system controller 25. The CPU 55 of the system controller 25 determines that the recording paper roll 4 is newly loaded in the roll chamber based on the detection signal of the optical sensor 23, and starts the calibration process. Thus, since the calibration process is performed when a new recording paper roll 4 is loaded, it is possible to always perform printing with an appropriate density and gray balance. In addition to the density abnormality caused by the printer, the density abnormality caused by the color development characteristics of the color thermal recording paper 3 can be corrected.

  The system controller 25 feeds the color thermal recording paper 3 from the recording paper roll 4 into the conveyance path by causing the motor driver 29 to rotate the conveyance motor 28 in the normal direction. The leading end of the color thermal recording paper 3 moves in the conveyance path, is nipped by the conveyance roller pair 32, and is further conveyed downstream in the A direction. When the leading edge of the color thermal recording paper 3 is detected by the optical sensor 44, counting of pulses supplied to the transport motor 28 is started. Thereafter, the transport position of the color thermal recording paper 3 is specified by the system controller 25 by this count value.

  When the print start position of the Y calibration pattern on the color thermal recording paper 3 reaches the print position of the thermal head 37, the rotation of the carry motor 28 is temporarily stopped. Next, the platen roller 38 is raised by the shift mechanism, and the color thermal recording paper 3 is sandwiched between the heating element array 39.

  The calibration data generation unit 57 generates print data of the Y calibration pattern 18 of “OD0.5” and inputs it to the head driver 42. The conveyance motor 28 resumes normal rotation, and the color thermal recording paper 3 is conveyed in the A direction. During this conveyance, the heating element array 39 generates heat based on the printing data, and the Y calibration pattern 18 is printed adjacent to the Y reference pattern 13.

  If the Y correction parameter is stored in the correction parameter memory 63 by the calibration process performed before the current calibration process, based on the Y correction parameter read from the correction parameter memory 63, The print density of the Y calibration pattern is corrected. Thereby, it is possible to calibrate the print density used before the current calibration process.

  When the Y calibration pattern 18 reaches a position facing the yellow fixing light source 48 of the optical fixing device 47, the rotation of the carry motor 28 is stopped. The platen roller 38 is lowered by the shift mechanism and forms a gap with the thermal head 37. Next, the yellow fixing light source 48 is turned on, the transport motor 28 is reversed, and the color thermal recording paper 3 is rewound in the B direction. As a result, the yellow thermosensitive coloring layer 9 at the tip of the color thermosensitive recording paper 3 is fixed.

  After the fixing of the yellow thermosensitive coloring layer 9 at the leading end of the color thermosensitive recording paper 3 is completed, when the printing start position of the M calibration pattern 19 reaches the printing position of the thermal head 37, the rotation of the carry motor 28 is temporarily stopped. Next, the platen roller 38 is raised, the color thermal recording paper 3 is sandwiched between the platen roller 38 and the heat generating element array 39, and the color thermal recording paper 3 is conveyed in the A direction by the forward rotation of the conveyance motor 28.

  Similar to the printing of the Y calibration pattern 18, the M calibration pattern 19 of “OD 0.5” is printed adjacent to the M reference pattern 14 of the color thermal recording paper 3. When the M correction parameter is stored in the correction parameter memory 63, the print density of the M calibration pattern 19 is corrected based on the M correction parameter.

  After printing the M calibration pattern 19, the magenta thermosensitive coloring layer 8 is fixed by the magenta fixing light source 49 while the color thermosensitive recording paper 3 is rewound in the B direction. After the fixing of the magenta thermosensitive coloring layer 8 is completed, a C calibration pattern 20 of “OD 0.5” is similarly printed adjacent to the C reference pattern 15. If there is a C correction parameter, density correction is also performed when the C calibration pattern 20 is printed.

  The front end portion of the color thermal recording paper 3 on which the reference patterns 13 to 15 and the calibration patterns 18 to 20 are printed is cut by the cutter 52 to become the sample print 21. The sample print 21 is discharged out of the color thermal printer 2 from the discharge port 34 by the discharge roller pair 33.

  The user observes the sample print 21 shown in FIG. 5 and selects the same density number as the density of the calibration patterns 18 to 20 from the reference patterns 13 to 15. Since the reference patterns 13 to 15 are printed on the same recording paper by the same printing method, they do not appear to have different colors depending on the observation light source. Moreover, since the reference patterns 13 to 15 are gradation and the calibration patterns 18 to 20 are printed in contact with the reference patterns 13 to 15, the density numbers of the calibration patterns 18 to 20 can be easily found.

  For example, in this embodiment, it is assumed that the density number of the Y calibration pattern 18 is “8” and the density numbers of the M calibration pattern 19 and the C calibration pattern 20 are “5”. In this case, the optical density values of magenta and cyan coincide with those of the reference printer, and the optical density value of yellow is higher than that of the reference printer. The color print created by the color thermal printer 2 in which the optical density value of each color varies has a gray balance.

  As shown in FIG. 7, a message “Y =?” Is displayed on the LCD 69 of the density number input unit 65. The user observes the sample print 21 and inputs the density number “8” specified by the ten key 67 and presses the enter key 68 to confirm the input content. Next, since “M =?” Is displayed on the LCD 69, the density number “5” is similarly input and confirmed. Finally, input of the cyan density number is similarly prompted by the LCD 69, which is entered and confirmed.

  The density number of each color input by the density number input unit 65 is stored in the density number memory 62. The calibration calculation processing unit 59 reads the density number of each color from the density number memory 62, and calculates a correction parameter for each color based on the graph of FIG. For example, in the yellow whose density number is “8”, the print density is too high compared to the reference printer. Therefore, a Y correction parameter is set so that the print density is lightened and stored in the correction parameter memory 63.

  Further, since the density number “5” for magenta and cyan has the same print density as that of the reference printer, density correction is unnecessary. Therefore, the M correction parameter and the C correction parameter are not calculated. If the print densities of magenta and cyan have been corrected based on the correction parameters of the calibration process performed previously, the M correction parameter and the C correction parameter are left in the correction parameter memory 63.

  As described above, since the density correction is automatically performed when the density number is inputted, anyone can easily perform the calibration process of the color thermal printer 2. Further, since the correction parameter can be calculated based on the density number, the correction parameter can be quickly obtained even when a system controller having a low processing capability is used.

  When the calibration process is completed, the color thermal printer 2 enters a print standby state. When printing is performed by the color thermal printer 2, when a yellow image is printed, the energization time to each heating element by the head driver 42 is adjusted by the Y correction parameter read from the correction parameter memory 63. . As a result, the print density of the yellow image is lowered to the same level as that of the magenta image and the cyan image, so that the color density is also equivalent to that of the reference printer, and the gray balance is improved.

  In the above embodiment, the reference pattern is printed on the color thermal recording paper by the reference printer, but the reference pattern may be printed by the marking device. Further, although the reference pattern and the calibration pattern are printed in contact with each other, they may be printed separately. Further, although the reference pattern is printed in gradation, a plurality of reference patterns having different optical densities may be printed. Further, although a color thermal printer using a recording paper roll has been described as an example, the present invention can also be applied to a color thermal printer using cut paper. Furthermore, although the calibration process is performed when the recording paper roll is set, the calibration process may be performed at an arbitrary timing.

  Moreover, although the said embodiment demonstrated the color thermal printer as an example, this invention is applicable also to a monochrome thermal printer. Furthermore, the present invention can also be applied to color printers and monochrome printers using recording methods other than thermal printers.

1 is a schematic diagram illustrating a configuration of a color thermal printer embodying the present invention. It is principal part sectional drawing which shows the layer structure of a color thermal recording paper. It is an external appearance perspective view which shows the structure of a recording paper roll. It is a top view of the color thermal recording paper which shows the form of a reference pattern. It is a top view of a sample print. It is a block diagram which shows the structure of a system controller. It is explanatory drawing of a density | concentration number input part. It is a graph showing the relationship between a density number and a density correction amount. It is a flowchart which shows the procedure of a calibration process. 6 is a flowchart illustrating a procedure of print processing.

Explanation of symbols

2 Color Thermal Printer 3 Color Thermal Recording Paper 4 Recording Paper Roll 13 Y Reference Pattern 14 M Reference Pattern 15 C Reference Pattern 18 Y Calibration Pattern 19 M Calibration Pattern 20 C Calibration Pattern 25 System Controller 37 Thermal Head 47 Optical Fixer 57 Calibration data generation unit 59 Calibration calculation processing unit 62 Density number memory 63 Correction parameter memory 65 Density number input unit

Claims (16)

A calibration pattern is printed with a predetermined optical density value of the recording head on a recording material on which a plurality of reference patterns having different printing densities are printed in advance.
The calibration pattern and each reference pattern are compared, and a reference pattern having a print density approximate to the print density of the calibration pattern is selected as a density approximate reference pattern.
A printer calibration method comprising adjusting the print density of a recording head based on a difference between the optical density value of the density approximate reference pattern and the predetermined optical density value used for printing the calibration pattern .   2. The printer calibration method according to claim 1, wherein the print density of the recording head is automatically adjusted by inputting a type of density approximate reference pattern to the printer.   3. The printer calibration method according to claim 1, wherein the reference pattern is printed by the same printing method by a reference printer or a marking device serving as a reference for printing density.   4. The printer calibration method according to claim 1, wherein the calibration pattern is printed adjacent to a reference pattern.   5. The printer calibration method according to claim 1, wherein the plurality of reference patterns are continuously printed in a gradation.   The recording material is a recording material roll in which a long recording material is wound in a roll shape, and a reference pattern of a plurality of types of printing densities is printed at the tip, and the recording material roll is referred to when being set in a printer. 6. The printer calibration method according to claim 1, wherein a calibration pattern is printed in the vicinity of the pattern.   The printer calibration method according to claim 6, wherein a front end portion of the recording material on which the reference pattern and the calibration pattern are printed is a blank portion to be cut and discarded.   The printer is a color printer that forms a color image by printing a plurality of different colors on a recording material, and prints the reference pattern and the calibration pattern for each color, compares each color, and 8. The printer calibration method according to claim 1, wherein the print density of the recording head is adjusted for each color.   The printer uses, as a recording material, a color thermosensitive recording paper in which first to third thermosensitive coloring layers that respectively color at least the first to third colors are formed on a support as a recording material. 9. The printer calibration according to claim 8, wherein the printer is a color thermal printer provided with a thermal head for selectively developing the first to third thermal coloring layers by applying specific thermal energy as a recording head. Method.   A recording head for performing printing on a recording material, calibration data generating means for generating printing data of a calibration pattern having a predetermined optical density value, and driving the recording head based on the printing data of the calibration pattern, thereby recording material A head driving unit that prints a calibration pattern in the vicinity of the reference pattern, an input unit that inputs a type of density approximate reference pattern selected as a reference pattern having a print density approximate to the print density of the calibration pattern, and A printer comprising density adjusting means for adjusting a print density of a recording head in accordance with input contents.   The density adjusting means adjusts the print density of the recording head based on the difference between the optical density value of the density approximate reference pattern and the predetermined optical density value used for printing the calibration pattern. Item 15. The printer according to Item 10. The recording material is a color thermosensitive recording paper in which first to third thermosensitive coloring layers that color at least the first to third colors, respectively, are provided on a support, and the recording head has each thermosensitive coloring. A thermal head for selectively developing the first to third thermosensitive coloring layers by applying heat energy peculiar to the layers,
The calibration pattern is printed for each of the first to third colors, the type of the density approximate reference pattern is input to the input unit for each of the first to third colors, and the density adjustment unit is 12. The printer according to claim 10, wherein the print density is adjusted for each of the third colors. In recording materials that are printed in the recording area by a printer,
A recording material wherein a plurality of types of reference patterns having different printing densities are printed in advance outside the recording area.   14. The recording material according to claim 13, wherein the plurality of reference patterns are continuously printed in a gradation.   15. The recording material according to claim 13, wherein the reference pattern is printed for each of a plurality of types of colors printed by a printer.   The recording material is a recording material roll in which a long recording material is wound in a roll shape, and a reference pattern is printed on a tip portion that is cut and discarded after printing on a recording area. The recording material according to claim 13.

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